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Introduction to the general parameters of PLC optical splitter

Nov. 27, 2021

Insertion loss: IL=-10Log(Po/Pi)  

Refers to the reduced value of the input end of the device and the corresponding output optical power.

Reflection/return loss:

RL/BR(Reflected on the contact end face, scattered inside the fiber) (return loss) RL=10Log(Pr/Pi)

RL in Chinese means foldback loss or return loss. When a certain CH of the device inputs the optical power of its corresponding wavelength, the optical device cannot penetrate 100%, and there will be a small amount of reflection back to the input end. This part of the optical power will be at the light emitting end. The resonant cavity is amplified, and its power level reaches a certain extent, which affects the emission stability and reliability of the light emitting instrument, and severely leads to the damage of the light emitting instrument. Therefore, it is necessary to control the foldback optical power, which is defined as the loss ratio of the foldback optical power relative to the optical power at the transmitting end.

Polarization dependent loss (PDL):

PDL is an important feature of optical fiber and optical communication devices, which has a serious impact on transmission quality. The PDL of individual devices will cause large power fluctuations in the system. Polarization-dependent loss is defined as the maximum insertion loss of the fiber or device in all polarization states. The difference value refers to the maximum change in the insertion loss of the corresponding port when the optical signal is input in different polarization states (such as linear polarization, circular polarization, elliptical polarization)

Temperature stability TDL:

Refers to the change of device insertion loss with temperature, expressed in dB/℃Temperature and wavelength drift: (△λ/T)

Refers to the wavelength shift caused by the device working wavelength changes with temperature, expressed in nm/℃

Polarization extinction ratio (PER):

After linearly polarized light passes through a section of optical fiber or passive components, a part of the optical power will be transferred to the polarization state orthogonal to the incident light. The polarization extinction ratio is defined as the optical power ratio between the original polarization direction and the orthogonal polarization direction expressed by logarithmic power

Additional loss (EL: also known as process loss) 

Refers to the loss of the total output power at each end to the input power. The additional loss is the most basic technical index of the splitter, and it is inherently related to other performance indexes. Therefore, the additional loss is not only a measure of the optical performance of the device, but more importantly, it is also intrinsically related to the shock resistance, temperature stability and service life of the device.

Directivity (DIR)   

DIR means directionality in Chinese. Assuming a 3Port device, the optical path loss of port1-port2 is 100% under ideal conditions. That is, the light path between port1 and port2 is obstructed, and no light can pass through. But because of the actual situation, this is not possible. Therefore, assuming that port1 will receive a small amount of optical power from port2 after inputting its CH wavelength, this is the source of DIR.

Coupling Ratio (CR)

CR= P1 /(P1+P2) * 100% is defined as the ratio of the power of a certain output terminal to the total power of all output terminals

Isolation (ISO)

The ISO solution is crosstalk (tone) or isolation. Since it is crosstalk (isolation), it is the interference between CH and CH. The ISO of a CH is usually defined as the difference between the minimum Loss of other CHs and the maximum Loss of the CH. That is to say, under ideal conditions, only light waves within the wavelength range of this CH should pass through this CH. But because of the limitation of the device manufacturing process, we can't actually realize the ideal situation. It will inevitably be partly transmitted through the CH when the light of other CH wavelengths is input. The specific impact on this CH depends on the difference between the ratio of optical power loss at the wavelength of the CH and the ratio of optical power loss when other CHs pass through the CH.

Uniformity/Uniformity (UF)

It is defined as the difference between the maximum value and the minimum value of the insertion loss of all the output ends of the device. This indicator mainly reflects the volatility of the insertion loss of the device.

Wavelength dependent loss (WDL)

The wavelength dependent loss is defined as the difference in the maximum insertion loss of the optical fiber or device within the specified wavelength range. Refers to the maximum change in insertion loss of the corresponding port when optical signals of different wavelengths are input (such as the range of 1310nm to 1620nm).